Pneum Systems Inc. Manufactures Duplex Filters with Working Pressure Up to 50 Bars. Pneum Systems Inc also offers air drying units, air filter, air receivers, after coolers and related compressed air accessories. The Duplex Filters with Working Pressure Up to 50 Bars are used for filtration of impurities. The Duplex Filters with Working Pressure Up to 50 Bars is a combination of carbon filter and micro filter. These Filters have filtration efficiency up to 8 ppm for oil content and 99% up to 5-10 micron for dust. These Filters are designed and constructed in accordance with pressure vessel codes.